Question

Answer 1

a) 2(x - 7) + 25 = 15

2(x - 7) = 15 - 25

2(x - 7) = -10

x - 7 = -10 : 2

x - 7 = -5

x = -5 + 7

x = 2

b) x ∈ Ư(50) = {-50; -25; -10; -5; -2; -1; 1; 2; 5; 10; 25; 50}

Mà -5 < x < 5

⇒ x ∈ {-2; -1; 1; 2}

Answer 2

a) \(2\left(x-7\right)+25=15\)

\(\Rightarrow2\left(x-7\right)=15-25\)

\(\Rightarrow2\left(x-7\right)=-10\)

\(\Rightarrow x-7=-10:2\)

\(\Rightarrow x-7=-5\)

\(\Rightarrow x=-5+7\)

\(\Rightarrow x=2\left(tm\right)\)

b) Ta có: \(x\inƯ\left(50\right)\)

\(\Rightarrow x\in\left\{1;2;5;10;25;50;-1;-2;-5;-10;-25;-50\right\}\)

Mà: \(-5< x< 5\) nên \(x\in\left\{-2;-1;1;2\right\}\)

Answer 3

a) 2(x - 7) + 25 = 15

2(x - 7) = 15 - 25

2(x - 7) = -10

x - 7 = -10 : 2

x - 7 = -5

x = -5 + 7

x = 2

b) x ∈ Ư(50) = {-50; -25; -10; -5; -2; -1; 1; 2; 5; 10; 25; 50}

Mà -5 < x < 5

⇒ x ∈ {-2; -1; 1; 2}